scholarly journals On the Surface Residual Stress Measurement in Magnesium Alloys Using X-Ray Diffraction

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5190
Author(s):  
Amir Yazdanmehr ◽  
Hamid Jahed

X-ray penetration in magnesium alloys is significant due to the low X-ray mass attenuation coefficient. To measure the surface residual stresses in magnesium alloys, a correction needs to be made to account for penetration depth. The residual stresses in as-received and shot peened AZ31B-H24 rolled sheet samples were measured using two-dimensional X-ray diffraction (2D-XRD) method. The electro-polishing layer removal method was used to find the residual stress pattern at the surface and through the depth. The results show that the corrected residual stresses in a few tens of micrometers layer from the surface differ from the raw stresses. To better estimate the residual stress distribution in the surface, the grazing-incidence X-ray diffraction (GIXD) technique was applied. Additionally, micrographs of the lateral cross-section of the peened specimens confirmed the presence of microcracks in this region, causing the residual stresses to vanish. Due to the low X-ray absorption coefficient of Mg alloys, this study shows how a small uncertainty in a single raw measurement leads to high uncertainty in the corrected residual stresses. The results were corroborated with the hole drilling method of residual stress measurements. The corrected X-ray diffraction (XRD) results are in close agreement with the hole drilling and GIXD results.

Author(s):  
Cameron Lonsdale ◽  
John Oliver

Railroad wheels are manufactured with beneficial residual compressive hoop stresses, which are imparted by rim quenching and tempering. Hoop and radial residual stresses for wheels have been studied in detail by various organizations over the years and are relatively well characterized. However axial residual stresses, in the orientation across the rim width from back rim face to front rim face, have not been extensively investigated. This paper describes a failure mode known as a vertical split rim (VSR) and describes efforts to measure the axial residual stresses in, 1) new wheels, 2) service worn wheels and 3) wheels that have failed from VSRs. Initial axial residual stress measurement efforts, using core drilling and x-ray diffraction from the tread surface, are briefly reviewed. Further more extensive work using x-ray diffraction to measure axial residual stress on radial wheel slices is described and data are presented, focusing on differences between the three wheel types. The concept of Axial Stress Amplification (ASA) is outlined, and the relationship of axial residual stress to VSRs is discussed. A proposed mechanism for VSR formation is described. Future work, with a goal of reducing or eliminating VSRs in service, is considered.


Author(s):  
Christopher M. Gill ◽  
Philip J. Withers ◽  
Alex Evans ◽  
Neil Fox ◽  
Koichi Akita

A layer of compressive residual stress extending from the surface of a component can help to extend fatigue life, but it must remain stable during applied service loading. Metal shot and glass bead peening are traditionally used; introducing a shallow (100–300μm) layer of compressive residual stress and a highly cold worked surface. Laser peening and deep rolling are capable of introducing much deeper compressive residual stresses combined with lower levels of cold work. In this paper we report on the level of shakedown of residual stress brought about by constant strain amplitude fatigue. Glass and metal shot peened, laser peened and deep rolled Ti-6Al-4V samples have been studied. The residual stress profiles as a function of depth have been measured using neutron diffraction, laboratory x-ray diffraction and a hybrid hole-drilling/laboratory x-ray diffraction method. The magnitude and depth of cold work determined for each of the treatment methods. The extent of subsequent residual stress shakedown under different strain amplitudes and load ratios, in deep rolled, glass bead and metal shot peened samples is also assessed.


2012 ◽  
Vol 554-556 ◽  
pp. 461-464 ◽  
Author(s):  
Rui Zhou ◽  
Lian Hong Zhang ◽  
Yu Hong Liu

Residual stresses in green compacts have a significant influence on the quality of the compact and post-compaction processes like part handling. In this study, the latest European and American standard for residual stress measurement by X-ray diffraction have been used to obtain more exact residual stresses in surface of green compacts as experimental evidence for simulation. The influence of kinds of powders, compacting pressure and friction on residual stresses in green compact has been studied.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Vladimir Ivanovitch Monine ◽  
João da Cruz Payão Filho ◽  
Rodrigo Stohler Gonzaga ◽  
Elisa Kimus Dias Passos ◽  
Joaquim Teixeira de Assis

In the present work, residual stresses in nickel-based (Ni 625) superalloy weld metal of a 9%Ni steel-welded joint were measured by X-ray diffraction (XRD). This technique presents some difficulties in performing measurements in coarse and preferentially oriented weld metal microstructures. It is proposed a preliminary surface treatment by rotating steel wire brushing to perform the stress analysis through XRD technique possible for this kind of material. Stress measurements with proposed XRD technique showed that the stress state in Ni 625 weld metal on the outside surface of the welded joint is characterised by tensile stresses in the transverse and longitudinal directions, while compressive transverse and tensile longitudinal residual stresses are developed in the root pass region.


2016 ◽  
Vol 879 ◽  
pp. 578-582
Author(s):  
Yi Fei Gao ◽  
Shu Lan Wang

Residual stress measurements were successfully performed on the representative IN718 fatigue specimens by X-Ray Diffraction. All surface residual stresses were found to be compressive. A stress gradient normal to the surface was observed on all specimens. The residual stresses tended to become less compressive with increasing depth into the parts. Residual stress measurement is the special requirement for NADCAP CRITERIA AC 7101/7. In this paper, residual stress measurements were successfully performed on two IN718 low cycle fatigue test specimens.


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1854
Author(s):  
Samuel Pulvermacher ◽  
Tobias Bücker ◽  
Jan Šaroun ◽  
Joana Rebelo-Kornmeier ◽  
Michael Hofmann ◽  
...  

Experimental analyses of depth distributions of phase-specific residual stresses after deep rolling were carried out by means of laboratory X-ray diffraction and neutron diffraction for the two duplex steels X2CrNiMoN22-5-3 and X3CrNiMoN27-5-2, which differ significantly in their ferrite to austenite ratios. The aim of the investigation was to elucidate to which extent comparable results can be achieved with the destructive and the non-destructive approach and how the process induced phase-specific micro residual stresses influence the determination of the phase- and {hkl}-specific reference value d0, required for evaluation of neutron strain scanning experiments. A further focus of the work was the applicability of correction approaches that were developed originally for single-phase materials for accounting for spurious strains during through surface neutron scanning experiments on coarse two-phase materials. The depth distributions of macro residual stresses were separated from the phase-specific micro residual stresses. In this regard, complementary residual stress analysis was carried out by means of incremental hole drilling. The results indicate that meaningful macro residual stress depth distributions can be determined non-destructively by means of neutron diffraction for depths starting at about 150–200 µm. Furthermore, it was shown that the correction of the instrumental surface effects, which are intrinsic for surface neutron strain scanning, through neutron ray-tracing simulation is applicable to multiphase materials and yields reliable results. However, phase-specific micro residual stresses determined by means of neutron diffraction show significant deviations to data determined by means of lab X-ray stress analysis according to the well-known sin2ψ-method.


2006 ◽  
Vol 514-516 ◽  
pp. 768-773
Author(s):  
Joao P. Nobre ◽  
Altino Loureiro ◽  
António Castanhola Batista ◽  
A. Morão Dias

In this work the reliability of the hole-drilling technique (HDT) for measuring welding residual stresses was analysed. HDT residual stress results were systematically compared with those determined by X-ray diffraction. A systematic overestimation of the residual stresses determined by HDT was observed, which was mainly attributed to the possibility of the so-called plasticity effect occurring. Experimental results were discussed taking the measurement principles of both techniques into consideration. In addition, preliminary results of a numerical study, using the finite element method, will be presented for a better understanding of the plasticity effect on HDT residual stress results.


1990 ◽  
Vol 34 ◽  
pp. 611-622
Author(s):  
J. Jo ◽  
R.W. Hendricks ◽  
R.E. Swanson ◽  
R.V. Foutz

AbstractA new failure criterion for discriminating good and bad (overheated) railroad car wheels is proposed using X-ray residual stress data. The procedure for the new discrimination criterion is based on the fluctuations of the azimuthal residual stress in the tread of the wheel. This criterion is based on a maximum likelihood statistical analysis of stress data obtained from six different wheels as determined by x-ray diffraction. Of these locations, the analysis showed the tread, and perhaps a critical point on the top of the flange, to be the most sensitive to residual stress. The variance analysis showed that fluctuations in stress a.l the most sensitive location in the tread to be related to the service history. The residual stresses showed an oscillatory pattern in the hoop direction around the wheels. Extension of the measurement technology to the use of faster residual stress measurements is proposed. To validate our x-ray residual stress data, residual stresses were also measured by hole drilling. Excellent agreement between two techniques was found.


Author(s):  
Y. P. Yang ◽  
R. Dull ◽  
T. D. Huang ◽  
H. Rucker ◽  
M. Harbison ◽  
...  

Welding, as a major manufacturing process in shipbuilding, induces residual stress and distortion that affects buckling strength, fatigue performance, corrosion resistance, and dimensional stability of ship structures. Understanding residual stress in ship structures is required in engineering design to ensure structural strength and safety and is essential in dimensional accuracy for distortion control during fabrication. However, measuring residual stress in ship structures presents unique challenges, such as structure complexity, surface primer, and a non-friendly measurement environment. Fortunately, portable X-ray diffraction equipment has been successfully developed and proven accurate in other industries to measure residual stress. This study is to evaluate the feasibility of measuring residual stress in a shipyard environment in terms of accuracy and adaptability. Typical welded joints (butt joint and T-joint) were selected for evaluation instead of evaluating complicated ship structures. The welded joints were fabricated using common shipyard welding procedures. This makes the evaluation easier since weld residual stress distributions and magnitudes on these joints are well understood. In addition, the hole-drilling method was also used to validate the X-ray diffraction results. Measured results show that X-ray diffraction can penetrate the pre-construction surface primer used in shipbuilding to directly measure residual stress of the metal surface, without the need to remove the surface primer. The residual stress data measured by X-ray diffraction agreed with the data obtained by the hole-drilling method. In addition, the residual stress trend measured by X-ray diffraction agreed with the theoretical residual-stress distributions. This study concluded that a portable X-ray diffraction is a potential technology for residual stress measurement in a shipyard.


2006 ◽  
Vol 524-525 ◽  
pp. 613-618 ◽  
Author(s):  
Bob B. He

This paper introduces the recent progress in two-dimensional X-ray diffraction as well as its applications in residual stress analysis in thin films. The stress measurement with twodimensional x-ray diffraction can be done with low incident angle and is not limited to the peaks with high two-theta angles like the conventional method. When residual stresses of thin films are measured, a low incident angle is preferred to maximize the diffraction signals from the thin films surfaces instead of from the substrates and matrix materials. Since one stress measurement at one fixed incident angle is possible, stress gradients in depth can be measured by series of incident angles. Some experimental examples are given to show the stress measurement at low and fixed incident angle.


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